Mechanical interactions in biological active filaments and networks

Active matter systems are those whose individual constituents convert energy to move or perform mechanical work. Physicists have long been fascinated by active matter systems as they are inherently out of thermal equilibrium, making them much more difficult to classify and quantify using the traditional techniques of statistical mechanics. Biology, being comprised of many such systems, has become one of the most sought-after fields for the physics community. In this work, we are predominantly interested in biological machines that consume chemical energy, like ATP, and use this fuel to exert forces on their surroundings. We utilize theoretical and computational techniques to investigate these systems as in silico is a cost effective way to span the parameter space and learn design principles that can both decipher the current generation of in vivo and in vitro experiments and propel the next. Here, we develop minimal mechanical models, conduct computer simulations, and apply quantitative analytics at the cellular level (chapters 2, 3, and 4) and subcellular scale (chapter 5) to both gain insight into relevant design principles and make testable predictions regarding the system constituents and emergent behavior thereof. Specifically, in chapter 2, we ask if cells modeled solely as coarse grained anisotropic contractile force dipoles are sufficient to produce branched multicellular network structures and how the mechanical properties of the substrate and cell response to the substrate affect this tendency. In chapter 3, we ask if cells modeled as contractile dipoles in a discretized elastic medium can give rise to a strong nonlinearity in force production as a function of density suggested by recent experiments of fibroblasts embedded in collagen gels. In chapter 4, motivated by a wide variety of systems like synthetic Janus colloids in an alternating electric field and magnetotactic bacteria, we explore the collective behavior of highly motile contractile anisotropic dipoles. Lastly, in chapter 5, we ask if the geometric helicity of microtubules coupled to motor propulsion is sufficient to produce emergent chiral motion of isolated microtubules, rather than a fundamental chirality given by intrinsic curvature

Nach Halle kam Hanau: Rezension zu "Antisemitismus, Xenophobie und pathisches Vergessen: Warum nach Halle vor Halle ist" von Helmut Dahmer

Helmut Dahmer: Antisemitismus, Xenophobie und pathisches Vergessen - Warum nach Halle vor Halle ist. Interventionen, II. Folge. Münster: Westfälisches Dampfboot 2020. 978-3-89691-258-

The influence of assistance in home-based exercise programs for individuals with intellectual disabilities

Indiana University-Purdue University Indianapolis (IUPUI)Intellectual disability (ID) is considered a high-incidence disability affecting approximately 1.2 million adults in America (Brault, 2012). Diagnosed before the age of 18, ID is characterized by poor intellectual functioning, difficulty with adaptive behaviors, and problems with activities of daily living. Adaptive behaviors include practical, social and conceptual skills. Individuals with ID may lack the ability to personally care for themselves, self-direct and display naïve decision-making capabilities. Activities of daily living, such as maintaining one’s health, are influenced by poor adaptive behaviors. Between the years of 1997 and 2008, the prevalence of developmental disabilities, including ID, has increased 2.2% and while there is research dedicated to determining the risk factors causing ID, there is a continued need to research adaptive behavior management (Boyle et al., 2011). Current research in adaptive behavior focuses on determining best practices in order to help adults with ID thrive in schools, the workplace, home, and in the community. Adaptive behaviors related to healthcare, self-direction, and personal care still continue to be an area of adversity for the population and research on prevalence of healthcare-related problems are growing (Ervin & Merrick, 2014). Health concerns increase with the severity of the ID as well as age (Moss et al., 1993; Schrojenstein et al., 1997). Over 40% of adults with ID will develop four or more chronic diseases with an increase in age (Hsieh, Rimmer, & Heller, 2012). In the typical population, there is a plethora of evidence demonstrating that regular physical activity (PA) reduces the risk for chronic diseases, specifically all-cause mortality, colon and breast cancer, hypertension, cardiovascular disease, obesity, and depression (American College of Sports Medicine, 2013). However, the number of adults with ID participating in regular PA is considerably lower than the typical population. This lack of participation increases individual risk for secondary health conditions. With diminished capabilities in adaptive behaviors, there are significant issues that affect this population’s ability for self-care and independence in health-related care. Additionally, there are limited opportunities for individuals to take steps to improve his or her ability for self-care. Improving the availability of quality instruction for PA and adherence may increase overall PA and reduce incidence and prevalence of chronic disease in adults with ID

Government Cloud Computing and the Policies of Data Sovereignty

Government cloud services are a new development at the intersection of electronic government and cloud computing which holds the promise of rendering government service delivery more effective and efficient. Cloud services are virtual, dynamic and potentially stateless which has triggered governments' concern about data sovereignty. This paper explores data sovereignty in relation to government cloud services and how national strategies and international policy evolve. It concludes that for countries data sovereignty presents a legal risk which can not be adequately addressed with technology or through contractual arrangements alone. Governments therefore adopt strategies to retain exclusive jurisdiction over government information